Drafting compass



May 17, 1927.

P. J. BUNGART DRAFTI NG COMPAS S Filed NOV. 18, 1922- ATTOR N EY Patented MayY 11,1927.

D STATES f PAUL J. .Brrivergin'igv orocnnivsinn, 'ivriw'vorvxgy v Appiieationiiiedivovember1s, maar. sriainmoi'eu. f

` For a detailed description of the present form of myl invention, reference may be had tothe following specification 4andto the. accompanying drawing forming apart thereof, wliereinv Y. Figlisaplanand j Fig. 2 a side elevation of my device; Q [Fig y3.s asection of the tripod and .A

Fig. 4 isa section of thespring-traveller. jMy invention comprises a drafting-com'- pass provided with a radial beam, a central support or tripod `for said'beam liavingan expanded base for firm seating on the drawing at; the center of an arc to be drawn anda spring-traveller 4for its outer end whichnorf mallygholds-the penv or other marker slightly f elevated above the drawing but maybe pressed down to put the pen .in contact with i the drawing for marking.`

Referring to Athek drawing, yA represents the radial beam or shaft of the compassy be- Y ing ordinarily made of wood. At its rear or centering end is a supporting tripod B which has an expanded circular basel B1 on the under side ofv which arethe retaining needle points b, b, Z). These points willA keep the base permanently in position during the drawing operation without any liability ofv defacing the drawing which frequently occurs when the beam is centered by a single pointed spike. Such a spike makes a large lhole in the drawing which becomes further enlarged by the repeated rotations of the spike therein, when many arcs are drawn from the same center. At the center lof the base B1 vis a circular openingV or window preferably covered with glass or other transparent hard substance on which hair lines cross each other at the exact centerl and extend overbase B. On l the upper end of tripod B is swiveled and hinged a block C Awhich carries the usual clamp C1 for beam VA. By means of the swivel joint between B and ,C the beam' may be rotated horizontally and by means of the hinge its outer end may be lifted away from the drawing y to enable'the draftsman to ink his pen for continuous work without the .interruption caused by lifting the compass. Y

At the outer end of the beam A. is a second clamp E1 on the under sideof which istlie pen or pencil F and back` of the pen or peni, cil is a lug E to which ishinged on'a transh4, a hollow shaft in which slides a rod or verse axis the traveller `or resilient 'support D. This traveller has, asappears in Fig.

shownjin dotted-lines in Fig. 2. VInopera'f tien the tripod' B willbe seated on the drawingd at the center ofthe arc to be drawn, the

hair .lines 'aforesaid 4being at the ,center of the are, said b aseBl` being rmly seated on thedrawing fand held'against zslidingfmOve:V i*

menti by the needle-.poiiits Then the beam A will be turned ldown till4 thelwlieellrvof the aforesaid traveller D rests on therrpaperf. .The springe@2 will still hold pen F a slight distance from the, drawing. The traveller Arian.; will then support the weight-ofthe guter* endof tliebeamlandthe latter may be `freely "l moved, acrosstlie paper; in an, arccentering at the-'axisfOi-th'e ,tripod Without, anmriark .Y being made on the paper.r To 'cause the pen,

pencil or marker to mark-,a slight pressure downward on the beam vwill compress the spring G2 of the. `traveller and put 'the marker into operating position onthe draw,- ing. This .foregoingarrangement relieves the operator of the burden of upholding the outer end of the beam and .enables him to set the marker to fthe exact point desired with complete accuracy, a screw Kbeing also employed tol adjust its` radial position.

lVliatl I claim as new and by LettersvPatent is:y n

l. A Vdrafting compass comprising a cen! tering support having a base ofsubstantial area provided with a central window, anchoring means for said base,a `radial beam, and means providing a swivelling and hinging joint between the beam and the support in aposition above said window,"wherebyv the view through the window is substantially unobstructed. j V f 'Y '2A drafting compass comprising a centering support, a -radial beam, a hinged support member for one end of said beam, said f support member having ladepending portion j n swivelled in saidV support, and 'means for resiliently supporting the other endof said l beam. p f Y 8. A' drafting swivelled in said centering support, -a marker; at the other end of said beam, and a resilient support for the free'end of said beam, said desire :to secure n compass comprisinga cenf i' tering support, aradial beam, ahinging supiA y. port member-for one end of said beam, saidz i Vsupport meinberhaving a dependingv portion Y' Y A Y 1,629,143

resilient; suppoitnormally aebingfto vlift the `markerlout lof Contact with the dra-Wing.

; 4. A drafting compass comprising. incen- CilA teringv suppot havinglzin. expended;barsefpyo L vlded with e, cent-ral Window, anhorlngf V means for sald base, a radial bez1m, means providing a swivelling and hinging ointbebweenrone end of thebeam, landbhe' oenterl ingsupport a position above the Window;V AWfhe'lebjr4v thel vievvfthouglfnthe Wlldovv'isV poljbforfthe beam, Seidl resilient support being positioned contiguous "fosztidmarker Vand{Iioiihally acting folift the merkel" out jfirdafjaing compass comprising u een@ terin supporti;v a radifel beam having v fswlv lingandihlnglng'oonneetion*et one end o 'nd 'a "spring-pressed*'supporting' plunger es@ 2r'Glen.Pieeers'eidibemi@wwwY plunger mountedin vsaid tube and provided y lwith a supporting roller, and means for limiting :movement ofi Saud plunger. f 7; A draftingeompasseompylsmga. radial bearn,' an independent centeringsupport'to Y which one 1 endl` of' sali'dbeam i is' hinged and swivelled, a clamp slidably mountedfonsa-id beam and provided v'v-ithatrevelling'suptrzivellingsupport." 'f fthe relative positions Lof-'zhe marker'andbhe 83. Ai limiti-ngompass-,eomprising 'al` radial i beam, ein independent ce1-itefing support :to

swivelled," afsl'idble carrier mounted .on yseid Y beam,k aiv marker anda travelling support independently j oiiit'ed f to f seidI sliding-1 car'- riet; 'and' meansfforr adjusting: the `elative positions of the marker and-the support alon'gLt-he-carrenf L PAUL 1J. BUN'QART 

